This invention relates to fluid fittings, and in particular, to fluid fittings used as a connector to effect a hydraulic seal for transmitting pressurized fluid.
Fluid fittings, such as connectors between two members transmitting a fluid, are common and used in many industrial, commercial, and residential applications. The actual fluid transmitted through the connectors, the temperature of the fluid, and the pressure of the fluid are parameters that define the performance characteristics required by a fluid fitting. In certain applications, unique connector assemblies have been developed in the art, while in other applications, conventional hard plumbing connections are used.
Conventional fuel oil burners generally include a fuel supply line. Each fuel supply line is connected at one end to a fuel supply pump and terminates at the other end at a burner inlet nozzle. A valve used to regulate fuel flow is included in the fuel supply line. The fuel oil is typically pumped under relatively high pressures. It is conventional in the prior art to hard plumb the supply line from the fuel oil pump, to the valve, and to the burner inlet nozzle. The plumbing operation uses conventional elbow fittings, threaded fittings, and nipples to effect a sealed supply line. The use of conventional plumbing requires the supply line to transverse space outside the immediate burner proximity.
Conventional burners of this type often are installed within an application environment by an original equipment manufacturer. A design concern for burner suppliers is to limit the volumetric footprint of the burner. The less volume the burner assembly occupies, the more advantageous the burner is to the original equipment manufacturers. Another design concern for connectors of this type is to effect a hydraulic seal at high pressure.
Conventional connectors typically mount the valve at a relative distance away from and above the burner nozzle line. To hard mount the valve, additional mounting hardware parts are required. During the off-cycle of a burner, air tends to gather in the nozzle line of the burner.
The air tends to result in less-reliable burner light-offs and shut-downs.
Another concern with convention plumbing is that in-the-field maintenance requires disassembly of the plumbing connections in order to service the valve or the burner. The disassembly increases maintenance costs and equipment down time.
Thus, there is a need for a connector providing a hydraulic seal for transmitting high pressure fuel oil which allows the hard mounting of a valve without valve mounting parts required, while at the same time minimizing air trapped in a nozzle line, while providing a reduced volumetric footprint attractive to original equipment manufacturers.
The present invention is directed to a fluid fitting suitable for connecting first and second members that transmit pressurized fluid. The fitting effects a hydraulic seal. In a preferred embodiment, the connector is directed to providing a connection for a fuel oil line leading from a valve to an oil burner. The first member of the connection is a standard flare fitting leading to an inlet nozzle line feeding a burner. The second member is valve including a standard pipe fitting.
The fluid fitting comprises an elongated tubular stem a first connecting member (e.g. a nut), a second connecting member (e.g. a plug), and a hydraulic seal. The elongated tubular stem comprises a first end portion having a first outer diameter, a flange having a second outer diameter and disposed at a second end portion of the stem, and an intermediate portion axially spaced between the first end portion and the flange. The intermediate portion has an outer diameter. A shoulder is disposed between the intermediate portion and the first end portion. An internal fluid passageway extends throughout the stem. The second diameter is larger than the intermediate portion diameter, while the intermediate portion diameter is larger than the first diameter.
The first connecting member comprises an inner opening extending therethrough that receives the intermediate portion of the stem and permits relative rotation between the first connecting member and the stem. An internal abutment surface engages the flange and prevents axial movement of the first connecting member on the stem. A threaded portion is adapted to engage threads of the first member to be connected to the fitting. A polygonal shaped exterior tool engaging surface is included. In a preferred embodiment, the first connecting member is a flare nut sized to engage a standard flare fitting.
The second connecting member comprises an inner opening extending therethrough which receives the first end portion of the stem. A threaded portion is adapted to engage threads of the second member to be connected to the fitting. An abutment face at one end engages the shoulder of the elongated tubular stem. A polygonal shaped exterior tool engaging surface is included. In a preferred embodiment, the second connecting member is a tapered pipe fitting.
The hydraulic seal may be comprised by an internal diameter of the inner opening of the second connecting member and the first diameter of the stem being sized effective to form an interference fit between the second connecting member and the first end portion of the elongated tubular stem.
In a preferred embodiment, the threaded portion of the first connecting member may comprise threads disposed on an internal surface and the threaded portion of the second connecting member comprises threads disposed on an external surface. An axial length of the first end portion of the stem may be longer than an axial length of said second connecting member. A diameter of the second member may be larger than a diameter of the first member, as in the case of an internal diameter of a threaded opening of a valve (second member) which is larger than an external diameter of a threaded nipple on a flare fitting (first member).
The invention also comprises the combination of the valve connector, the valve, and the flare fitting attached to a fuel conduit of a burner.
A method for assembling a fluid fitting assembly, suitable for connecting first and second members that contain pressurized fluid, comprises the first step of providing an elongated tubular stem according to the present invention. A first connecting member according to the present invention is oriented such that the threaded portion of the first connecting member is directed toward the first end portion of the elongated stem. The first connecting member is slipped over the first end portion such that the flange of the elongated tubular stem contacts the internal abutment surface of the first connecting member.
A second connecting member is oriented such that the threaded portion of the second connecting portion is directed away from the first end portion of the elongated stem. The first end portion is inserted into the interior opening of the second connecting member such that the second connecting member contacts the shoulder of the elongated tubular stem.
The threaded portion of said first connecting member is connected to a threaded portion of the first member. The threaded portion of the second connecting member is connected to a threaded portion of the second member.
In a preferred embodiment, the first end portion of the stem is staked onto a tapered end of the second connecting member by the use of a tool.
The present invention offers advantages over connectors available in the prior art. A connector in accordance with the present invention permits a valve to be rigidly mounted to a nozzle line feeding an oil burner without the use of any additional valve mounting hardware. During the off-cycle of a burner, air tends to gather in the nozzle line of the burner. A connector assembled in accordance with the present invention can be rigidly mounted at the height of the nozzle line. Mounting in this location advantageously minimizes air trapped in the nozzle line. Further, the valve may be mounted within the limited spacing directly adjacent the burner, minimizing unused space and an overall volume occupied by the burner system. No connector in the prior art permits this accomplishment.
Many additional features, advantages and a fuller understanding of the invention will be had from the accompanying drawings and the detailed description that follows. It should be understood that the above Summary of the Invention describes the invention in broad terms while the following Detailed Description of Preferred Embodiments describes the invention more narrowly and presents preferred embodiments which should not be construed as necessary limitations of the broad invention as defined in the claims.